The History of the Jefferson Nickel (1938-present):

The first Jefferson Five Cent Piece was issued in 1938. The obverse
design of Thomas Jefferson has remained unchanged and is still in use today.
Likewise, the original reverse design of Monticello is still current. The mint
mark however has undergone some changes over the years.

The mint mark on Jefferson Five Cent Pieces from 1938 to midway
through 1942 was located on the right side of the reverse between Monticello
and the rim. When the composition changed in 1942, the mint mark was enlarged
considerably and moved to the field above Monticello. These 1942-1945 wartime
silver issues marked the first use of a P mint mark on a United States coin. In
1946 the original mint mark location was resumed. Jefferson Five Cent Pieces
from 1968 to the present have their mint mark on the obverse, near the rim,
just below the last digit in the date. Nickels struck in Philadelphia from 1938
- 1942 and from 1946 - 1979 bear no mint mark.

The Jefferson Five Cent Piece was designed by Felix Schlag. His
initials, F S, which were added in 1966, appear on the obverse near the rim
under the bust of Jefferson. Schlag was the winner of $1,000.00, and the honor
to put his design on the new nickel five cent piece, in an open design
competition.

The Jefferson Five Cent Piece was originally composed of 75% copper and
25% nickel. This composition was used until midway through 1942. During that
time the nickel was needed for the war effort so the composition was changed to
56% copper, 35% silver, and 9% manganese. In 1946, after WWII had ended, the
original composition was resumed. Jefferson Five Cent Pieces have a weight of
5.00 grams, a diameter of 21.2 mm and a plain edge. Jefferson Five Cent Pieces
were struck in Philadelphia, Denver, and San Francisco. (five cent pieces
struck in Philadelphia from 1938 - 1942 and 1946 - 1979 bear no mint mark).

SMS (Special Mint Set): Made 1965-1967 at the Philadelphia Mint.
No Proof Sets were produced these years.

1 and 2: The 1979 Type 1 coins have a "filled S" which was hard
to read. The die was re-cut creating the Type 2 or "clear S." Similarly, in
1981, the dies for the coins were re-cut creating a Type 1 (Rounded S) and a
Type 2 (Flat S).